Abstract:
The compressive strength of core concrete is affected by many parameters and one of them is the strength of the concrete, which affects the strength of the core compressive strength. This is achieved by using correction factors present in several standards such as ASTM C 42/C 42M-04, but this standard was not considered for high and very high strength concrete (HSC). In this study, a beam of (1x 4x 0.2) m constructed with 100 MPa target strength for core samples. Four different core diameters (25-50-75-100) mm and for each diameter different core length-diameter ratios(λ=l/d) (2-1.75-1.5-1.0) were extracted from the beam for assessing the strength in both casting directions. The relationship between the strength of concrete with respect to reference samples and different cores size with different slenderness ratio, length to diameter (λ) were investigated. The Ultrasonic Pulse Velocity (UPV) was conducted for all samples and the relationship between UPV and strength of cores were determined. The results showed that the core strength was increased with the decrease of slenderness ratio. Core samples correction factors to predict the strength of standard cylinder for HSC beam are different from normal strength concrete (NSC) and they have ranged between 1.0 and 1.12 for beam. Relationship between core compressive strength and UPV values are established.
